Toyota Avalon (XX50): Check Bus 2 Line for Short to +B. Check Bus 2 Line for Short to GND. Check Bus 2 Lines for Short Circuit

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Power Source, Network / Networking / Can Communication System(for Gasoline Model) / Check Bus 2 Line for Short to +B. Check Bus 2 Line for Short to GND. Check Bus 2 Lines for Short Circuit

Check Bus 2 Line for Short to +B

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and +B when there is no resistance between terminal 18 (CA4H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3.

Symptom	Trouble Area
There is no resistance between terminal 18 (CA4H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3.	Short to +B in CAN main bus line Central gateway ECU (network gateway ECU) ECM No. 2 CAN junction connector No. 4 CAN junction connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

NOTICE:

Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.
Click here
Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.
Click here
After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
DTC check procedure: Turn the engine switch on (IG) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.
After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.
Click here

HINT:

Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.
When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE

1.	CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 2 CAN JUNCTION CONNECTOR)

(a) Disconnect the cable from the negative (-) battery terminal.

(b) Disconnect the A49 No. 2 CAN junction connector.

DLC3

Front view of wire harness connector

(to No. 2 CAN Junction Connector)

to No. 4 CAN Junction Connector

to ECM

Standard Resistance:

Tester Connection	Condition	Specified Condition	Connected to
A49-10 (CANH) - G45-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	No. 4 CAN junction connector
A49-21 (CANL) - G45-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	No. 4 CAN junction connector
A49-11 (CANH) - G45-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	ECM
A49-22 (CANL) - G45-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	ECM

Result	Proceed to
OK	A
NG (Line to ECM)	B
NG (Line to No. 4 CAN junction connector)	C

REPLACE NO. 2 CAN JUNCTION CONNECTOR

GO TO STEP 3

2.	CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 2 CAN JUNCTION CONNECTOR - ECM)

(a) Disconnect the A18 ECM connector.

(b) Measure the resistance according to the value(s) in the table below.

DLC3

Front view of wire harness connector

(to No. 2 CAN Junction Connector)

to ECM

Standard Resistance:

Tester Connection	Condition	Specified Condition
A49-11 (CANH) - G45-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
A49-22 (CANL) - G45-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

Result	Proceed to
OK	A
NG	B

REPLACE ECM

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 2 CAN JUNCTION CONNECTOR - ECM)

3.	CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 4 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)

(a) Disconnect the G96 No. 4 CAN junction connector.

(b) Measure the resistance according to the value(s) in the table below.

DLC3

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

to No. 2 CAN Junction Connector

Standard Resistance:

Tester Connection	Condition	Specified Condition
G96-11 (CANH) - G45-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
G96-22 (CANL) - G45-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)

4.	CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 4 CAN JUNCTION CONNECTOR)

(a) Disconnect the G95 No. 4 CAN junction connector.

(b) Measure the resistance according to the value(s) in the table below.

DLC3

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance:

Tester Connection	Condition	Specified Condition
G95-1 (CANH) - G45-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
G95-12 (CANL) - G45-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

REPLACE NO. 4 CAN JUNCTION CONNECTOR

5.	CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 4 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

(a) Disconnect the G52 central gateway ECU (network gateway ECU) connector.

(b) Measure the resistance according to the value(s) in the table below.

DLC3

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance:

Tester Connection	Condition	Specified Condition
G95-1 (CANH) - G45-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
G95-12 (CANL) - G45-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

Check Bus 2 Line for Short to GND

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and GND when there is no resistance between terminal 18 (CA4H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Symptom	Trouble Area
There is no resistance between terminal 18 (CA4H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.	Short to ground in CAN main bus line Central gateway ECU (network gateway ECU) ECM No. 2 CAN junction connector No. 4 CAN junction connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

NOTICE:

Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.
Click here
Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.
Click here
After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
DTC check procedure: Turn the engine switch on (IG) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.
After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.
Click here

HINT:

Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.
When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE

1.	CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 2 CAN JUNCTION CONNECTOR)

(a) Disconnect the cable from the negative (-) battery terminal.

(b) Disconnect the A49 No. 2 CAN junction connector.

DLC3

Front view of wire harness connector

(to No. 2 CAN Junction Connector)

to No. 4 CAN Junction Connector

to ECM

Standard Resistance:

Tester Connection	Condition	Specified Condition	Connected to
A49-10 (CANH) - G45-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 4 CAN junction connector
A49-21 (CANL) - G45-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 4 CAN junction connector
A49-11 (CANH) - G45-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	ECM
A49-22 (CANL) - G45-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	ECM

Result	Proceed to
OK	A
NG (Line to ECM)	B
NG (Line to No. 4 CAN junction connector)	C

REPLACE NO. 2 CAN JUNCTION CONNECTOR

GO TO STEP 3

2.	CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 2 CAN JUNCTION CONNECTOR - ECM)

(a) Disconnect the A18 ECM connector.

(b) Measure the resistance according to the value(s) in the table below.

DLC3

Front view of wire harness connector

(to No. 2 CAN Junction Connector)

to ECM

Standard Resistance:

Tester Connection	Condition	Specified Condition
A49-11 (CANH) - G45-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
A49-22 (CANL) - G45-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

Result	Proceed to
OK	A
NG	B

REPLACE ECM

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 2 CAN JUNCTION CONNECTOR - ECM)

3.	CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 4 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)

(a) Disconnect the G96 No. 4 CAN junction connector.

(b) Measure the resistance according to the value(s) in the table below.

DLC3

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

to No. 2 CAN Junction Connector

Standard Resistance:

Tester Connection	Condition	Specified Condition
G96-11 (CANH) - G45-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
G96-22 (CANL) - G45-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)

4.	CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 4 CAN JUNCTION CONNECTOR)

(a) Disconnect the G95 No. 4 CAN junction connector.

(b) Measure the resistance according to the value(s) in the table below.

DLC3

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance:

Tester Connection	Condition	Specified Condition
G95-1 (CANH) - G45-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
G95-12 (CANL) - G45-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

REPLACE NO. 4 CAN JUNCTION CONNECTOR

5.	CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 4 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

(a) Disconnect the G52 central gateway ECU (network gateway ECU) connector.

(b) Measure the resistance according to the value(s) in the table below.

DLC3

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance:

Tester Connection	Condition	Specified Condition
G95-1 (CANH) - G45-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
G95-12 (CANL) - G45-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

Check Bus 2 Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the CAN main bus lines and/or CAN branch lines when the resistance between terminals 18 (CA4H) and 17 (CA4L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

Symptom	Trouble Area
Resistance between terminals 18 (CA4H) and 17 (CA4L) of the central gateway ECU (network gateway ECU) is below 54 Ω.	Short in CAN main bus lines Central gateway ECU (network gateway ECU) ECM No. 2 CAN junction connector No. 4 CAN junction connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

NOTICE:

Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.
Click here
Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.
Click here
After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
DTC check procedure: Turn the engine switch on (IG) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.
After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.
Click here

HINT:

Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.
When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE

1.	CHECK FOR SHORT IN CAN BUS LINES (NO. 2 CAN JUNCTION CONNECTOR)

(a) Disconnect the cable from the negative (-) battery terminal.

(b) Disconnect the A49 No. 2 CAN junction connector.

Front view of wire harness connector

(to No. 2 CAN Junction Connector)

to No. 4 CAN Junction Connector

to ECM

Standard Resistance:

Tester Connection	Condition	Specified Condition	Connected to
A49-10 (CANH) - A49-21 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 4 CAN junction connector
A49-11 (CANH) - A49-22 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	ECM

Result	Proceed to
OK	A
NG (Line to ECM)	B
NG (Line to No. 4 CAN junction connector)	C

REPLACE NO. 2 CAN JUNCTION CONNECTOR

GO TO STEP 3

2.	CHECK FOR SHORT IN CAN BUS LINES (NO. 2 CAN JUNCTION CONNECTOR - ECM)

(a) Disconnect the A18 ECM connector.

(b) Measure the resistance according to the value(s) in the table below.

Front view of wire harness connector

(to No. 2 CAN Junction Connector)

to ECM

Standard Resistance:

Tester Connection	Condition	Specified Condition
A49-11 (CANH) - A49-22 (CANL)	Cable disconnected from negative (-) battery terminal	1 MΩ or higher

Result	Proceed to
OK	A
NG	B

REPLACE ECM

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 2 CAN JUNCTION CONNECTOR - ECM)

3.	CHECK FOR SHORT IN CAN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)

(a) Disconnect the G96 No. 4 CAN junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

to No. 2 CAN Junction Connector

Standard Resistance:

Tester Connection	Condition	Specified Condition
G96-11 (CANH) - G96-22 (CANL)	Cable disconnected from negative (-) battery terminal	1 MΩ or higher

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)

4.	CHECK FOR SHORT IN CAN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR)

(a) Disconnect the G95 No. 4 CAN junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance:

Tester Connection	Condition	Specified Condition
G95-1 (CANH) - G95-12 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

REPLACE NO. 4 CAN JUNCTION CONNECTOR

5.	CHECK FOR SHORT IN CAN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

(a) Disconnect the G52 central gateway ECU (network gateway ECU) connector.

(b) Measure the resistance according to the value(s) in the table below.

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance:

Tester Connection	Condition	Specified Condition
G95-1 (CANH) - G95-12 (CANL)	Cable disconnected from negative (-) battery terminal	1 MΩ or higher

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

Check Bus 1 Lines for Short Circuit

Check Bus 3 Line for Short to +B. Check Bus 3 Line for Short to GND. Check Bus 3 Lines for Short Circuit

See More:

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